1. Field of the Invention
The present invention relates to a manufacturing method of a semiconductor device and an etching solution.
2. Related Art
At the time of etching silicon or polysilicon in an RIE (Reactive Ion Etching) process, a mixed gas of a halogen gas (Br gas and a CI gas, for example) and oxygen is used as an etching gas. In this case, a SiO2 deposit is formed.
At the time of etching a silicon oxide film or a silicon nitride film in the RIE process, a CF (fluorocarbon) gas is used as an etching gas. In this case, a CF deposit is formed.
Therefore, when a lamination film of a polysilicon film and a silicon nitride film is continuously etched by RIE, both a SiO2 deposit and a CF deposit are adhered to the etched result as etching residues. After this RIE, it is necessary to continuously execute a remove processing of the SiO2 deposit and a remove processing of the CF deposit. For example, it is necessary to carry out a process as a combination of an oxidation process of the CF deposit by means of a dry ashing, an SPM (sulfuric acid and hydrogen peroxide mixture) process, an alkali process, a DHF (diluted hydrofluoric acid) process, a VPC (vapor HF) process, and the like. When these processes are combined, the number of steps of processes after the RIE increases. Further, the DHF process etches a gate insulation film and a silicon oxide film of STI (Shallow Trench Isolation) and the like. Therefore, the use of the DHF process after forming the STI and the gate insulation film is not preferable.